OFFSET
1,2
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Lara Pudwell, Systematic Studies in Pattern Avoidance, 2005.
Index entries for linear recurrences with constant coefficients, signature (1,1,2,3,1).
FORMULA
G.f.: x*(1 + x)*(1 + 2*x^2 + x^3) / (1 - x - x^2 - 2*x^3 - 3*x^4 - x^5).
a(n) = a(n-1) + a(n-2) + 2*a(n-3) + 3*a(n-4) + a(n-5) for n>5. - Colin Barker, Oct 20 2017
PROG
(PARI) Vec(x*(1 + x)*(1 + 2*x^2 + x^3) / (1 - x - x^2 - 2*x^3 - 3*x^4 - x^5) + O(x^40)) \\ Colin Barker, Oct 20 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Lara Pudwell, Feb 26 2006
STATUS
approved